Heat exchanger

ABSTRACT

A heat exchanger having a first flow channel, through which a first fluid can flow, and having a second flow channel, through which a second fluid can flow, whereby the first flow channel has a first section, a second section, and a redirection region, whereby the first section is in fluid communication with the second section via the redirection region and the second fluid can flow around the first section, the second section, and the redirection region, and whereby the first section and/or the second section of the first flow channel are each formed by a plurality of tubes.

This nonprovisional application claims priority under 35 U.S.C. §119(a) to German Patent Application No. DE 10 2013 221 151.1, which was filed in Germany on Oct. 17, 2013, and which is herein incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to a heat exchanger having a first flow channel, through which a first fluid can flow, and having a second flow channel, through which a second fluid can flow, whereby the first flow channel has a first section, a second section, and a redirection region, whereby the first section is in fluid communication with the second section via the redirection region and the second fluid can flow around the first section, the second section, and the redirection region.

2. Description of the Background Art

So-called U-flow heat exchangers are used in many applications. These heat exchangers are characterized in that the fluid flowing through the heat exchanger flows in at one end region of the heat exchanger and is redirected by approximately 180° at an end region lying opposite to this end region. The fluid in this case ultimately again flows out of the heat exchanger at the end region where it had come in.

Heat exchangers with such a configuration are used, when the installation space no longer allows the use of heat exchangers with a conventional throughflow or other boundary conditions support their use.

It is advantageous with such a heat exchanger that approximately double the cooling section is available with the same overall length. It is a disadvantage, however, that only a smaller cross section per cooling section is available, which has a negative effect on the arising pressure loss.

Numerous heat exchangers are prior in the art. Thus, DE 10 2004 019 554 B4, which corresponds to U.S. Pat. No. 7,077,114, discloses an exhaust gas recirculation system for a combustion engine. The exhaust gas recirculation system in this case has a heat exchanging unit, which comprises a heat exchanger, with a redirection of the cooling fluid by approximately 180°. The heat exchanger to this end has a U-shaped flow channel. As a result, both the fluid inflow of the flow channel and the fluid outflow are arranged at the same end region of the heat exchanger. A second fluid flows around the flow channel in this case in the region of the forward flow, in the region of the backward flow, and in the region of the redirection, as a result of which a heat transfer between the fluid within the flow channel and the fluid flowing around the flow channel is achieved.

It is particularly disadvantageous in the solutions in the prior art that the redirection region of the heat exchanger is either cooled not at all or cooled only by the air surrounding the heat exchanger. Furthermore, the maximum heat transfer is often too low in the case of heat exchangers which provide flow around the flow channel including the redirection region.

SUMMARY OF THE INVENTION

It is therefore an object of the present invention to provide a heat exchanger which has a temperature-controllable redirection region and is optimized with respect to its efficiency compared with the conventional art.

An exemplary embodiment of the invention relates to a heat exchanger having a first flow channel, through which a first fluid can flow, and having a second flow channel, through which a second fluid can flow, whereby the first flow channel has a first section, a second section, and a redirection region, whereby the first section is in fluid communication with the second section via the redirection region and the second fluid can flow around the first section, the second section, and the redirection region, whereby the first section and/or the second section of the first flow channel are each formed by a plurality of tubes.

A heat exchanger redirected along its flow direction is especially advantageous, because on the whole the overall length of the heat exchanger can be made shorter than in a heat exchanger with a linear flow. A redirection region around which a second fluid flows is advantageous, because thereby an additional heat transfer option is created within the heat exchanger, as a result of which the efficiency or performance of the heat exchanger can be increased. The first section and/or the second section of the first flow channel are advantageously made of tubes.

Tubes are especially advantageous, because they can be manufactured at reasonable cost and are available on the market in many different forms. The heat transfer surface can be increased overall by a plurality of tubes, around whose outer surface a fluid can flow, as a result of which an improved heat transfer can be achieved between the fluid within the tubes and the fluid outside the tubes.

The heat exchanger can have a housing, which is formed as a single part or as multiple parts with at least one first housing part and a second housing part.

A better mountability can be achieved by the multiple-part design. In addition, the housing can possibly be better adapted to the design of the heat exchanger. In particular, undercuts can be realized by a multiple-part housing; these cannot be realized, for example, by a one-part deep-drawn housing.

The housing can be manufactured from an aluminum material and produced in a pressure casting process. In this regard, either all housing parts or only individual housing parts can be produced in this way. Alternatively, the housing or individual housing parts can be manufactured from a steel material, for example, stainless steel, or a plastic. Housings or housing parts made of plastic can thereby be produced by an injection molding process.

The housing can form at least partially the second flow channel. Advantageously, the housing surrounds the first flow channel in such a way that a hollow space, which forms the second flow channel, arises between the outer walls of the first flow channel and the inner walls of the housing. Flow around the first flow channel can be achieved by the flow through this second flow channel, as a result of which heat transfer between the fluid in the first flow channel and the fluid in the second flow channel can be produced.

In addition, the first housing part can surround the first and second section and the second housing part can surround the redirection region.

This type of separation can achieve an especially advantageous and cost-effective adaptation of the housing to the heat exchanger. In particular, the sections can be surrounded advantageously by a simple cuboid structure, whereas the redirection region can be surrounded, for example, by another housing part, which can be configured in the form of a deep-drawn cover, for example, and can be produced in a separate production process.

In an embodiment, the tube bottom with a cover can form a collecting tank, whereby the inner volume of the collecting tank forms the redirection region. In this way, a fluid-tight redirection region can be produced by known manufacturing methods.

A flow section of the second flow channel, the section through which the second fluid can flow, can be formed between an outer wall bounding the redirection region and an inner wall of the housing and/or a wall of the first flow channel.

This flow section is exemplary, because along this section the second fluid, which can be a cooling fluid, can flow around the redirection region. In this way the heat transfer surface between the first fluid and the second fluid is increased overall, as a result of which the efficiency of the heat exchanger is improved.

In an embodiment, turbulence inserts and/or cross-section-narrowing components can be arranged along the flow section on the outer wall of the redirection region and/or on the inner wall of the housing.

The fluid flow in the flow sections can be advantageously influenced by turbulence inserts such as, for example, guide ribs, corrugated profiles, elevations, and depressions on the surface or by other means for influencing the cross section. For example, the actively throughflown flow cross section can be influenced, which has a direct effect on the arising pressure loss within the heat exchanger. The course of the flow within the flow section can also be influenced by flow guiding device of this type.

The housing can have a first fluid connection and a second fluid connection, over which the second fluid can be supplied to the housing and can be removed from the housing.

In an exemplary embodiment of the invention, it can be provided that the first section and the second section and/or the redirection region of the first flow channel can be integrated into the housing, which forms at least partially the second flow channel, in such a way that the second flow channel is sealed fluid-tight against the first flow channel and/or the redirection region and the environment.

A fluid-tight sealing of the flow channels against the respectively other flow channel and the environment is especially advantageous to assure the functionality of the heat exchanger. In the case of a not completely fluid-tight design, mixing of the fluids could occur, which can lead to damage to the heat exchanger and/or in upstream and downstream components.

In an embodiment, all tubes can be mounted at least in the same end region in a tube bottom. The tubes are advantageously mounted in the same end region in a tube bottom. This increases the stability of the heat exchanger. Furthermore, an especially simple connection to a fluid supply line and a fluid drain line can be achieved by providing a tube bottom at the same end region.

The fluid supply and fluid removal of the first flow channel can be arranged at the same end of region of the heat exchanger. This enables an especially compact structural form of the heat exchanger.

The first fluid can be a gas and the second fluid can be a coolant. Cooling of the fluid flowing in the first flow channel can be advantageously achieved in this way. Greater cooling of the first fluid or the gas can be achieved by cooling in the first section, in the second section, and in the redirection section.

Further, the second fluid can have a lower temperature level than the first fluid. The second fluid can be used for cooling the first fluid. The second fluid can thereby be advantageously incorporated into a cooling circuit, in order to always assure the lowest possible temperature level for the second fluid. Depending on the design of the heat exchanger, the second fluid in an alternative embodiment, however, can also have a higher temperature level than the first fluid. This applies particularly when the heat exchanger is used for heating the first fluid.

The first fluid can be redirected by 180° in the redirection region along its flow direction. A redirection of approximately 180° is especially advantageous, because in this way fluid connections can be provided at the same end region of the heat exchanger. In alternative embodiments, redirections can also be provided, which have a different angle or, for example, two redirections with 90° each.

Depending on whether only the first and second section or also the redirection region is arranged in the housing, the maximum transferable amount of heat can be greater or smaller. An arrangement in which a second fluid, which can be a cooling fluid, flows around both the sections and the redirection region is particularly advantageous.

Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawings which are given by way of illustration only, and thus, are not limitive of the present invention, and wherein:

FIG. 1 shows a perspective view of a heat exchanger mounted in a housing and redirected by 180° in its throughflow direction;

FIG. 2 shows a perspective view of the heat exchanger according to FIG. 1;

FIG. 3 shows an alternative perspective view of a heat exchanger mounted in a housing;

FIG. 4 shows a perspective view of an alternatively designed heat exchanger according to FIG. 3;

FIG. 5 shows a further alternative view of a heat exchanger mounted in a housing, which is redirected in its throughflow direction by 180°;

FIG. 6 shows a perspective view of the heat exchangers according to FIG. 5;

FIG. 7 shows a sectional view through a conventional heat exchanger redirected by 180° in its throughflow direction; and

FIG. 8 shows a sectional view of a heat exchanger of the invention with an additional flow section, which surrounds the redirection region.

DETAILED DESCRIPTION

FIG. 1 shows a perspective view of a heat exchanger 1. Heat exchanger 1 is surrounded by a housing 2. Housing 2 has on its outer side a plurality of fins 5, which increase the structural stiffness of housing 2. To this end, fins 5 are distributed on housing 2 in a manner suitable in terms of load. Furthermore, housing 2 has a holding member 4, with which heat exchanger 1 can be attached to a surrounding structure. Moreover, housing 2 has a fluid connection 3 through which a fluid can be conveyed into housing 2. A tube bottom 6, which belongs to heat exchanger 1 inserted in housing 2, is indicated at the bottom end region of heat exchanger 1.

Housing 2 can be made of a plastic, which can be processed, for example, in a pressure casting method. Alternatively, metallic materials can also be used.

FIG. 2 shows a perspective view of heat exchanger 1, as it is arranged in housing 2 of FIG. 1.

Heat exchanger 1 has in its bottom area a tube bottom 6 in which a plurality of first tubes 8 and second tubes 9 are mounted. In this case, tubes 8 and 9 are arranged depthwise in two adjoining tube stacks with a number of tubes. A first fluid flows through tubes 8 along flow direction 10 and the first fluid flows through tubes 9 along flow direction 11.

The change in direction between tubes 8 or tubes 9 occurs in the top redirection region 7. Redirection region 7 is substantially formed by a tube bottom 16, in which tubes 8, 9 are mounted and a box-like cover 17, which is inserted in this tube bottom, as a result of which an inner volume, in which the fluid can flow from tubes 8 into tubes 9, is produced within redirection region 7.

First tubes 8 thereby form a first section 12 of a first flow channel 15 and second tubes 9 form a second section 13 of a first flow channel 15. Overall, tubes 8 and 9 and redirection region 7 form first flow channel 15.

A second fluid can flow around first flow channel 15 within housing 2. For this purpose, a second flow channel 14 is formed within housing 2. In this way, a heat exchange can be produced between the first fluid both along tubes 8 of redirection region 7 and tubes 9. Overall, therefore the heat transfer between the first fluid and the second fluid can be considerably increased, because particularly redirection region 7 is also involved completely in the heat transfer between the first fluid and the second fluid.

Furthermore, a coolant guiding device, which surrounds tubes 8 and tubes 9, is shown in FIG. 2. The task of the coolant guiding device is to influence the flow of the fluid flowing within the housing. This should primarily prevent that a short-circuit flow forms within the housing and thus the fluid flows directly from the fluid inlet to the fluid outlet. This can occur particularly when the fluid inlet and the fluid outlet are arranged on the same housing side. Furthermore, the fluid can also be guided selectively between tubes 8, 9 in such a way that a possibly optimal surrounding flow and thereby improved heat transfer occur. Furthermore, an increase in the stability of heat exchanger 1 can also be achieved by the coolant guiding device.

In advantageous embodiments, fluid connections, which can be arranged, for example, on a collecting tank, can be provided below tube bottom 6. A fluid can be supplied by means of these to tubes 8 and separately therefrom a fluid can be removed from tubes 9.

FIG. 3 shows an alternative embodiment of a heat exchanger 21. Heat exchanger 21 is mounted within housing 22. Housing 22 is preferably made of a metallic material. Ideally, housing 22 is made of an aluminum.

Housing 22 has a plurality of holding members 24 with which housing 22 or heat exchanger 21 can be attached to surrounding structures. A tube bottom 26, which belongs to heat exchanger 21 inserted in housing 22, is indicated in the bottom end region of housing 22.

FIG. 4 shows a perspective view of heat exchanger 21, as it is disposed in the interior of housing 22 of FIG. 3. Tube bottom 26 has a plurality of tubes 28 and tubes 29, which are mounted in tube bottom 26. Tubes 28 and 29 are arranged in tube bottom 26 similar to the arrangement of tubes 8 and 9 of FIG. 2 in tube bottom 6. Tubes 28 thereby form a first section 36 of a first flow channel 39 and tubes 29 form a second section 37 of first flow channel 39. Tubes 28 and 29 in FIG. 4 furthermore are surrounded by a coolant guiding device similar to FIG. 2, as a result of which the fluid flow within heat exchanger 21 can be improved overall and particularly short-circuit flows of the fluid between the fluid inlet and the fluid outlet of the housing can be avoided.

A first fluid flows through tubes 28 along flow direction 30 and the first fluid flows through tubes 29 along flow direction 31. The redirection of the fluid occurs in redirection region 27.

Tube bottom 26 also has openings 32 and 33, apart from the openings in which tubes 28 and 29 are placed. Through these, the interior of housing 22 or second flow channel 38, formed in the interior of housing 22, can be supplied with a fluid or the fluid can be removed from the interior of housing 22. To this end, the tube bottom has a circumferential lip, which is run both around openings 32, 33 and tubes 28 and 29. This lip during the mounting of housing 22 comes to lie against an interior wall of the housing and thus serves to seal housing 22 from tube bottom 26.

In an alternative embodiment, a sealant can be provided further at this lip. Apart from this lip, tube bottom 26 has a number of openings, which can be used, on the one hand, for the screwing together of tube bottom 26 with housing 22 and also for connecting fluid connections to tube bottom 26 in order to supply tubes 28 with a first fluid or to remove the first fluid from tubes 29.

Redirection region 27, which is formed similar to FIG. 2 by a tube bottom 23 and a cover 25 inserted in this tube bottom, has turbulence inserts or flow guiding elements 34 on the upwardly directed outer wall. Turbulence inserts 34 are formed in such a way that the gap, which arises between the outer wall of redirection region 27 and the inner wall of housing 22, is influenced in such a way that the fluid flow of the second fluid, which flows within housing 22, is optimized. A flow section 35 is formed in the region between redirection region 27 and the inner wall of housing 22. Turbulence inserts 34 can influence both the width of said flow section 35 along redirection region 27 and also the distribution of the second fluid within said flow section 35.

To this end, housing 22 like housing 2 of FIG. 1 as well is designed in such a way that at least between redirection region 27 or redirection region 7 and the interior of housing 22 or 2 a sufficient large gap remains, which is formed as flow section 35 and through which second fluid can flow within housing 22 or 2. Moreover, the second fluid also flows around tubes 28 and 29, as a result of which a heat transfer between the first fluid within tubes 8, 9, 28, 29 of heat exchanger 1, 21 and the second fluid in housing 2, 22 of heat exchanger 1, 21 can occur along the entire heat exchanger 1, 21.

FIG. 5 shows a further perspective view of a heat exchanger 41, which is arranged within a housing 42. Housing 42 is formed in two parts and has a substantially cuboid region 42 and a housing part 45 connected thereto or placed on this region. Fluid connections 43 and 44 for supplying or removing a second fluid in housing 42 are provided on cuboid housing part 42. A tube bottom 46 of heat exchanger 41 is indicated in the lower end region of housing 42.

FIG. 6 shows a view of heat exchanger 41, as it is arranged in housing 42 of FIG. 5. In the view of FIG. 6, housing part 42 and housing part 45 are not shown. Fluid connections 43 or 44 of housing 42 are also shown.

Heat exchanger 41 has a plurality of first tubes 48 and a plurality of second tubes 49, which are arranged similar to FIGS. 4 and 2. Flow passes through tubes 48 along flow direction 50 and these tubes form a first section 52 of first flow channel 55. Flow passes through tubes 49 along flow direction 51 and these tubes form a second section 53 of first flow channel 55.

In an alternative embodiment, the flow direction, as it is indicated in FIG. 6 and the previous FIGS. 2 and 4, can also be reversed.

The redirection between tubes 48 and tubes 49 occurs along redirection region 47, which similar to the previous figures is formed by a tube bottom 56 and a cover 57 inserted therein. The second fluid can flow around both tubes 48, 49 and redirection region 47, whereas the first fluid flows through them. To this end, housing 42, 45 forms a second flow channel 54. In this way, a complete heat transfer also occurs both at tubes 48, 49 and redirection region 47.

FIG. 7 shows a sectional view through a conventional redirected heat exchanger 61. It has a plurality of tubes 68, through which flow occurs along flow direction 70, and a plurality of tubes 69, through which flow occurs along flow direction 71. Tubes 68, 69 are mounted in their left region in tube bottom 63 and in their right end region in tube bottom 64. Tube bottoms 63 and 64 are each mounted within housing 62 in an enlarged region 65, 66. Advantageously, tube bottoms 64, 64 are welded or soldered with housing 62.

Within redirection region 67, which similar to the previous figures is formed by a cover inserted in tube bottom 64, the fluid flow of the first fluid is redirected from tubes 68 to tubes 69. This is shown with flow direction 73 within redirection region 67.

The cover is inserted within tube bottom 64 advantageously with a sealing element 72. A form-fitting connection, alternatively also a material bonding connection, can be produced between tube bottom 64 and the cover, for example, by gluing, soldering, or welding.

Only a first fluid flows through heat exchanger 61, shown in FIG. 7, along tubes 68, 69 and through redirection region 67. A second fluid can flow through housing 62.

A cooling second fluid does not flow around redirection region 67 in the illustration in FIG. 7, so that the heat transfer in heat exchanger 61 occurs only along tubes 68 and 69. Thereby, overall the heat transfer section is reduced in comparison with the previous figures, as a result of which the overall transferable amount of heat is reduced. Redirection region 67 can only be exposed to the surrounding medium such as, for example, air, as a result of which both an additional cooling of the first fluid and also an unwanted heating of the second fluid can occur.

FIG. 8 shows a sectional view through a heat exchanger 81. A heat exchanger 81 is shown in FIG. 8, as it was already shown in FIG. 5 or 6. Heat exchanger 81 has a plurality of first tubes 88 and a plurality of second tubes 89, through which flow occurs according to flow direction 90 or 91. First tubes 88 form a first section 97 and second tubes 89 form a second section 98. The two sections 97, 98 together with a redirection region 87 form a first flow channel 100.

Tubes 88, 89 are mounted at the end sides in tube bottoms 83 or 84. Tubes 88 or 89 are surrounded by housing 82. A second flow channel 99, through which a second fluid can flow, is formed between tubes 88, 89 and housing 82. In the left widened region 86, tube bottom 83 is inserted fluid-tight in housing 82. In the right widened region 95, housing 82 is connected fluid-tight with housing part 85 in such a way that redirection region 87 and tube bottom 93 are mounted within housing part 85.

Between housing part 85 or an inner wall of housing part 85 and an outer wall of redirection region 87, flow section 94 is generated, through which, like the free space between tubes 88 and 89, the second fluid flowing within housing 82 can flow through along second flow channel 99.

Flow section 94, as already indicated in FIG. 4, can be formed by reducing the cross section or by turbulence inserts such that an optimal heat exchange occurs between the first fluid in redirection region 87 and the second fluid in flow section 94. In particular, the arising pressure loss in flow section 94 can be influenced by the provision of means for reducing the cross section of flow section 94 and/or turbulence inserts.

Redirection region 87 as in the preceding figures is formed by cover 101, which is inserted in tube bottom 84 and is sealed with a sealant 93, in such a way that the fluid flow of the first fluid within redirection region 87 is separated from the fluid flow of the second fluid inflow section 94 or within housing 82. The redirection within redirection region 87 occurs along flow direction 96.

Housings 2, 22, 42, 45, 82, and 85 can be made both of a plastic and of a metallic material. The suitable material is to be selected adapted to the working conditions. Provided a second fluid flows through the respective housing 2, 33, 43, 45, 82, and 85, the connection between the particular tube bottoms 6, 16, 23, 26, 46, 56, 83, 84 and housing 2, 22, 42, 82 or additional housing part 45, 85 must be made fluid-tight in such a way that no leakage to the environment or into the circulation of the first fluid occurs.

An increase in the cooling performance of heat exchanger 1, 21, 41, 81 can be achieved overall by the additional flow of a cooling fluid around redirection region 7, 27, 47, 87. It must be particularly considered hereby that the arising pressure loss within heat exchanger 1, 21, 41, 81 due to the measure should not increase if possible or only increases to a low extent.

All features of FIGS. 1 to 6 and 8 can be combined individually with one another. Embodiments 1 to 6 and 8 are not limiting in nature. Particularly with respect to the dimensions, geometry, and the arrangement of the individual components to one another and the material selection, FIGS. 1 to 6 and 8 are exemplary and are used to clarify the inventive concept.

The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are to be included within the scope of the following claims. 

What is claimed is:
 1. A heat exchanger comprising: a first flow channel through which a first fluid flows; and a second flow channel through which a second fluid flows, wherein the first flow channel has a first section, a second section, and a redirection region, wherein the first section is in fluid communication with the second section via the redirection region and the second fluid flows around the first section, the second section, and the redirection region, and wherein the first section and/or the second section of the first flow channel are each formed by a plurality of tubes.
 2. The heat exchanger according to claim 1, wherein the heat exchanger has a housing, which is formed as a single part or as multiple parts with at least one first housing part and a second housing part.
 3. The heat exchanger according to claim 2, wherein the housing forms at least partially the second flow channel.
 4. The heat exchanger according to claim 2, wherein the first housing part substantially surrounds the first and second section and the second housing part substantially surrounds the redirection region.
 5. The heat exchanger according to claim 2, wherein the tube bottom with a cover forms a collecting tank, and wherein an inner volume of the collecting tank forms the redirection region.
 6. The heat exchanger according to claim 2, wherein a flow section of the second flow channel is formed between an outer wall bounding the redirection region and an inner wall of the housing and/or a wall of the first flow channel.
 7. The heat exchanger according to claim 6, wherein turbulence inserts and/or a cross-section-narrowing component are arranged along the flow section on an outer wall of the redirection region and/or on an inner wall of the housing.
 8. The heat exchanger according to claim 2, wherein the housing has a first fluid connection and a second fluid connection, over which the second fluid is supplied to the housing and is removed from the housing.
 9. The heat exchanger according to claim 2, wherein the first section and the second section and/or the redirection region of the first flow channel is integrated in the housing, which forms at least partially the second flow channel such that the second flow channel is sealed fluid-tight against the first flow channel and/or the redirection region and the environment.
 10. The heat exchanger according to claim 1, wherein all tubes are mounted at least in a same end region in a tube bottom.
 11. The heat exchanger according to claim 1, wherein the fluid supply and fluid removal of the first flow channel are arranged at a same end region of the heat exchanger.
 12. The heat exchanger according to claim 1, wherein the first fluid is a gas and the second fluid is a coolant. 